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In the largest action to date, the FBI, state investigators and the attorney general have raided the offices of Sun Orthodontix.

Sun doesn't have locations in North Texas, but it was the second largest biller for braces under Medicaid in 2010.

Part of its huge growth in Texas is linked to Medicaid dental bills. News 8 found Texas dentists were charging taxpayers for putting braces on kids who didn't qualify for them under Medicaid.

Sun collected more than $9.6 million in 2010, according to state records.

FBI agents were part of Monday's raids at Sun offices, which stretch from El Paso to Corpus Christi.

"The FBI doesn't show up when they think you've committed a crime... they know you've committed a crime long before they show up," said Houston attorney Jim Moriarty, who is part of a whistle-blower case against Dallas-based All Smiles Dental Centers.

The joint raid is the largest action so far against a dental firm in Texas.

"I think you may see tens or hundreds of dentists who end up with civil or criminal charges against them," Moriarty said. "I think there is a tsunami of criminal action against crooked orthodontists in Texas."

No criminal charges have been filed against Sun or its dentists. But the company has been in a dispute with Medicaid. The state quit paying Sun Orthodontix earlier this year, questioning its practices.